They airbrushed the FAQ on 12 November to remove mention of the minimum one week mission target, and inserted among other things '2.5 days'. [2] A diff of the two versions would probably be interesting.
Now with the lander mission prematurely ended an associated scientist is tweeting a very rosy summary [3]:
"What a perfect ending. All the science completed, data received. Primary mission successful. Well done everybody."
How can a week of carefully-planned scientific activities be 'completed' in only 2.5 days? It seems implausible.
How did the primary and secondary batteries not power the lander for the calculated one week+ of operation?
Why aren't they open about what clearly seems to be a major failure with the scientific mission?
It seems a case of intense bureaucratic / political pressure to change targets after they aren't met, and the fact scientists are participating in this is pretty disappointing.
[1] https://web.archive.org/web/20140805030451/http://www.esa.in...
[2] http://www.esa.int/Our_Activities/Space_Science/Rosetta/Freq...
[3] https://twitter.com/rocketeddy/status/533421309553016832
http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29
"Rosetta was set to be launched on 12 January 2003 to rendezvous with the comet 46P/Wirtanen in 2011.
This plan was abandoned after a failure of the Ariane 5 carrier rocket during a communications satellite launch on 11 December 2002, grounding it until the cause of the failure could be determined."
No reason to blindly stick to the initial target when you're doing something for the first time ever. It's not that you planned to drive from your home to the shopping mall and have to excuse to your other that you went drinking beer instead. You would probably complain that it's not an initial comet now too?
The device landed on the darn comet! After travelling 6 billion km in 10 years. Managed to work a few days and send the data! First time ever! Powered only by the solar energy! (+) In the outside temperature of absolute zero. How many firsts do you need?
https://www.youtube.com/watch?v=uEY58fiSK8E
Nothing built by humans was ever on the comet surface before. This thing even worked.
+) Edit: Thanks to jdiez17 for pointing that the lander used a non-rechargeable battery on the comet surface. It was all the time planed to do the main work with that battery. The solar powered work wasn't the primary objective.
Your response relies on an appeal to emotion rather than logic, and doesn't seem particularly interested in engaging with the substance of the questions raised?
That's bad for science. It's quite similar to adjusting your hypothesis to fit the data. Not as bad as manipulating the data, but not ethical, either.
Yes, they want to give things a positive spin, but they aren't being disingenuous. They have learned a lot from this, and they got to run tests with all of the equipment on the lander. Calling it a major failure is way off base. You often learn more from things going wrong than from when they go right. Maybe not the things you were planning on learning, but this is very far from a failure.
I also think you're over-interpreting their "minimum mission target". That was an "if everything goes to plan" target. Everything didn't go as planned, but here's the thing: that's also in the plan. It is not possible to do this kind of mission without things going wrong. Usually when things go wrong, you get no data back. But despite the landing going terribly awry, we still got a lot of data back!
If you consider this a failure or a disappointment, then I'm glad you don't work for the ESA. You are far too cynical to be able to get this kind of science done.
Honestly it looks more like live rewriting of the FAQ to take into account the fact that Philae had a bumpy landing. I don't see an intention to deceive. It's awkward to present the document without mentioning it's not the detailed mission objectives.
That maybe the `perfect ending` considering we have some data back and well.. it's the only ending we have so rosetta exploding before philae could even be launched might have been labeled `perfect` too because it's the first time we put something into the orbit of a duck-like comet.
They certainly wished they had more philae time though. That would have been even more perfect. I wouldn't qualify this a `major failure` though (does the hostility come from that ?).
> The science observations will start immediately. During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.
And then:
> The science observations will start immediately. During the first 2.5 days the first series of scientific measurements will be completed. During this phase the lander will operate on primary battery power. In a second phase that may last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.
As the answers change, the FAQ page changes. The previous version of that page on the Internet archive doesn't mention the landing at all. So this isn't even a long standing promise. Probably they were making estimates and new guesses every few days as they got closer to the comet and learned more about it. The target mission duration probably depended on the location they landed, which wasn't decided until a few weeks ago. Anyway, the FAQ page is not the official mission planning document, and it's not meant to be a history of every change in the plan. It's a place to answer questions that the public and the press have about the current state of the mission.
I think people in general have come to expect the incredible lifetime of the Mars landers as the norm. It's not.
But since this is HN, I'm sure we all in the IT world are pretty confident in our estimations and our projects are a complete success all the time. Might explain why we are so disappointed with ESA. </sarcasm>
Failure happens and is nothing to be ashamed of when trying for such an ambitious goal. ESA needs to own it and move on.
It would have been great if it had worked of course, but compared to the main objective it doesn't really matter. What they really want to know is the chirality of the water on the comet and wether or not the comet contains certain elements, it seems like they manage to get this data.
Also the secondary objective is not totally abandonned, since there is still a chance to see Philae back in some months, with the comet getting much more sunlight and warming considerably.
Plans change with time, and the FAQ is adapted to those plan. Hell iirc there wasn't even suppose to be a lander in there initial plan 25 years ago.
This is a big leap to make from the available evidence. Mission targets change all the time. It's a very fluid situation with many unknowns, so I don't find it at all surprising. I think calling foul play is premature to say the least.
Until 12 November the FAQ [1] stated:
During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.
Editing to omit the minimum mission target on 12 November [2] indicates something was already wrong at that stage, which would presumably relate to the two batteries that were to power the lander over more than a week, but no public announcement of any issue like that was made. So we should instead assume the batteries were fully operational.
Instead we have ESA announcements and news articles asserting that the reason for the very short period of operation was a lack of solar power, but solar was never planned to be required for over a week at least.
It seems obvious that they had a battery failure. That would not be surprising, but why not openly announce it?
[1] https://web.archive.org/web/20140805030451/http://www.esa.in...
[2] https://web.archive.org/web/20141112043243/http://www.esa.in...
This ain't some piddly kickstarter trinket. And exactly what was promised that you didn't get your money's worth for?
Speaking as a researcher in the biological sciences, funded by public tax-payer sources only (don't forget, I also pay taxes), the risk of failure is absolutely astronomical with every project I have ever undertaken. The fact that those projects have succeeded the way they did, is, at least in my mind, phenomenal. Even then, none of these projects, or any projects of any other scientist in my field, have ever achieved all their stated goals.
If this rankles you, move to a place without public funding of science and bet your money on trinkets put up on kickstarter. Or if they are not trinkets, but are true attempts at solving hard problems(curing HIV/cancer, landing on a comet), I hereby guarantee that none of them will succeed 100% of their stated targets.
Parent never stated he wanted his money's worth. He points out some obvious history rewriting which highly harm Science's image (IMNSHO). In no way does that diminishes this mission's outcome, results, feats and the admiration it rightly deserves.
I don't understand the hostility here for a valid question about something that has nothing to do (obligatory political rewriting, maybe ?) with what was achieved.
> I hereby guarantee that none of them will succeed 100% of their stated targets.
But you don't lower your expectations after the facts and state "look, we did it as we told we were going to do it".
Human nature. Haven't you worked in a corporate environment where people try to spin to the positive? A lot of money was spent and people want to feel good about the results.
When they sold the project, the PowerPoint needed to present a great show or it wasn't going to get funded. A 1 week minimum was probably needed.
Anyway, I could go on but just try observe human nature, otherwise people will accuse you of being negative.
As for me, I thought it turned out to be a great because it became a mainstream story. We should be putting 4k video cameras on new craft. Get people excited so we can get a budget to build 10 times as many vehicles.
At a guess, the primary science mission was done so quickly because that's what they did. They might have spent more watts on locating the lander, for instance, or on taking pretty pictures.
Just search for "[-" to find deleted entries and "{+" to find added entries.
This is essentially the European Union's modus operandi.
We can expect the years of scientific papers based on the analysis of the raw data made by this mission.
The mistake would be allowing others to feed on smaller-effect non working stuff instead of the things that amazingly worked.
The harpoons failed to deploy leading the lander to bounce off of its landing target and land in a crater where the solar panels intended to increase its battery life had limited sunlight. http://www.vox.com/2014/11/13/7214941/philae-comet-rosetta
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2. The secondary rechargeable battery was designed to continue powering it for months after that.
The detail you include is only relevant to 2, and keep in mind it is reasonable to assume that the secondary battery was fully charged before descent.
The original mission parameters were well documented--that has not changed because an FAQ was edited. There will undoubtedly be a detailed technical review that investigate every change from plan to execution. Again, a website FAQ is not the forum for that.
> @ESA_Rosetta I'm feeling a bit tired, did you get all my data? I might take a nap… #CometLanding
> Thank you, @ESA_Rosetta! I did it! I became the first spacecraft to land on a comet & study it! But it’s not over yet… #CometLanding
> My #lifeonacomet has just begun @ESA_Rosetta. I'll tell you more about my new home, comet #67P soon… zzzzz #CometLanding
Good night, little lander. Hope you dream of electric sheep.
Imposter by The Doubleclicks https://www.youtube.com/watch?v=pHU67s5tOSA
If that is the case it's a massive shame - irrational fear of nuclear technology does a lot of damage.
It's certainly not "fear" of the nuclear technology in Europe that prevented something. See for example:
http://en.m.wikipedia.org/wiki/Nuclear_power_in_France
It's that the engineering tradeoffs have to be considered.
While there were certainly some political aspects to the question, there were other more pressing reasons to not pursue an RTG design. First and foremost (as others have pointed out) is the lack of knowledge towards this technology within the EU/ESA member states. Also, there's little left of the fuel usually used for these generators (238-PuO2 in space applications), and while it can be bred, none was produced for centuries (last time I checked). It is expected that NASA can only launch a couple of addtional RTG-powered missions before its ressources are depleted.
An RTG also poses quite a few engineering challenges for the spacecraft itself. They are huge and heavy with low efficiency, and their design requires them to be positioned on the outside with sufficient surface area to radiate away their heat. One of their main benefits – almost constant power for a long time – is also their biggest flaw: Their power output cannot be regulated.
While these challenges are in no way unsolvable (they are used both in space and on Earth), they require a certain spacecraft design which makes them unsuitable for many missions. If you take a look at the design of Philae and where it was attached to Rosetta, there is no way an RTG would have fit the design and mission characteristics chosen.
They could have chosen a different design. Though the question is then: Would this have changed anything wrt science output and/or success of the mission? I personally don't think so: An RTG would have increased cost and complexity without a significant impact on science output. An RTG would not have helped with the harpoon and ADS (cold gas thruster) issues which are the primary reasons why Philae landed in the shadows.
Though certainly a malfunction has happened, I do not consider this mission a failure, quite the opposite is true! Due to the hopping, there's a slew of unexpected science data which awaits to be analyzed. Additionally, there's still the chance that Philae may regain enough power once the comet is closer to the sun. Lastly, the primary mission objective – analyzing a comet – is still well underway with Rosetta orbitting Tschurie.
Another source I read at the time of the announcement said it will take a while to spin up, so there are some mission constraints over the next ten years. A Europa mission would wipe out existing supplies.
Anyone has a clue or educated guess?
edit thanks to all answers provided, exactly the info I was looking for! And very interesting as well.
I'm using the Mars Science Laboratory as an example here:
The MSL uses twin PowerPC RAD750 boards. If one of them fails, the rover could use the other as a backup. After all, you can't go out to Mars to fix a firmware update gone wrong. :) The RAD750's are hardened against radiation in space, and can withstand extreme temperatures. They run at about 200Mhz, and cost around $200.000 a piece. [1] [2]
It runs the realtime operating system VxWorks, which also happens to be what Apple uses for their Airport routers. :) [3]
NASA uses C as their main language, with specific coding standards. [4]
[1] http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Rover [2] http://en.wikipedia.org/wiki/RAD750 [3] http://www.extremetech.com/extreme/134041-inside-nasas-curio... [4] http://lars-lab.jpl.nasa.gov/JPL_Coding_Standard_C.pdf
Any idea how that works practically? I mean, there are two boards and one set of peripherals. Is there like an external controller which constantly checks if board A is doing fine, and if not, somehow reroutes all peripheral communication to board B?
http://space.stackexchange.com/questions/593/on-board-comput...
Note that the RTX2010 uses Forth:
Alongside real time OS like VxWorks, QNX, Aonix, ....
There was a presentation at CppCon about Mars Rover.
"Why was RTG (Radioisotope thermoelectric generator) not used in Rosetta mission?"
https://news.ycombinator.com/item?id=8610585
Only US and Russia have the technology.
The lander data includes infrared imagery, x-ray spectroscopy results, electrical conductivity measurements, temperature readings (from harpoons), acoustic data, gas analysis and magnetometer data http://nssdc.gsfc.nasa.gov/nmc/experimentSearch.do?spacecraf...
Hence the paucity of hard data released to the public; the organisations have first dibs on the data to make their money back through publications and in attracting research funding.
As an example: http://www.mps.mpg.de/1979387/MPS-Beteiligungen_an_Rosetta
Basically, ESA provide the bus on which the science kit rides.
As an EU tax-payer I've raged against this in the past but that's just the way it is.
Source: direct question on this matter that I put to an ESA PR at a public lecture about Rosetta.
Edit: most of it will be, not everything, as I've just found out.
Let's hope it will wake up and be reborn.
The chances for this seem not that bad, since the comet will heat up considerably as it approaches the sun, which will make it unnecessary to preheat the interior of Philae before starting to charge the batteries, while at the same time increasing the solar power reaching the panels (due to the sun being closer), so the lander might actually generate enough power to recharge the batteries and come alive again. Let's keep our fingers crossed.
I hope humanity grew up, so that failures would not produce so much backlash. Seems everybody feels so entitled in this age.
Mars Express and Venus express were based on similar hardware.
I mean, I'm sure Rosetta has neither (in useful conditions), but there's a thought for next time :/
http://www.lemonde.fr/sciences/article/2014/11/13/philae-peu...
You would need a flat surface to reflect light towards Philae, so the only appropriate surface would be the solar panels. The solar panels are not mirrors however, they would probably only reflect about 5%-10% of the sunlight towards Philae. This is even assuming the solar panels are sufficiently flat.
Also the location of Philae is unknown (AFAIK), so there is the problem of where to aim the reflected light.
Finally the relative direction from Rosetta would presumably change as the comet rotates, which means the solar panels or Rosetta as a whole would need to be continuously aimed at Philae, using propellant and/or other energy.
Despite geostationary satellites operating in an environment that's nominally -265 or so degrees celcius, the problem they usually experience is overheating, not freezing. Blackbody radiation will eventually carry the heat away, but we're talking decades to get to -100 or so.
For instance, a human body at rest generates about 150 watts of power, which would kill you in geostationary orbit without a cooling system. It would kill you because it wouldn't take long for your body temperature to rise to 52 degrees, at which point your cell metabolism abruptly stops (your mitochondria will stop generating energy). It would take longer than it takes you to choke though. Though nobody's ever tried for obvious reasons, you should be able to exit a space station and get back in with just a helmet that protects your mouth and nose and ears from decompression. You wouldn't freeze, you wouldn't explode. You'd overheat in 10-15 minutes or so. If you survive that, you'd die 2 weeks later from radiation poisoning. On the moon you need heating, because it actually has an atmosphere that would carry heat away.
It is fun reminiscing about just how special our place in the universe is. Human bodies wouldn't be able to survive on planets 30% closer to the Sun, or about 15% farther away. We wouldn't be alive without a mostly oxygen atmosphere, because without the ozone layer, solar radiation would kill us. Without the earth magnetic field, solar radiation would kill us. Without the sun protecting us from interstellar radiation, we'd die. If our solar system was further to the outside of the milky way, we wouldn't survive the radiation, solar protection or not. If it was closer to the middle, we wouldn't survive. It's unknown whether it's a black hole at the center or something else, but it sure outputs a lot of radiation. Oh, and we're in the < 0.1% of the milky way that hasn't experienced a supernova explosion for about 3 billion years (a supernova explosion at 20 lightyears or less would kill all life on earth. 50 lightyears is considered the minimum safe distance for large mammals to survive). The milky way has collided with at least 3 other (tiny) galaxies, none of the collissions were (are) anywhere near us, as the tidal stresses would alter planetary orbits, and so on and so forth.
All of this is ignoring the physical necessities for life to exist. If the fine structure constant, for instance, was 0.1% bigger or smaller, there would be no chemistry, and no humans. If the speed of light was ~5% bigger or smaller, there would be no atoms, as there would not be any stable electron orbitals, and so on.
What's the process for penalising posts in this situation?
Is it just an individual decision where you've decided it distracts from a valuable discussion?
I see I could have been a little less harsh with the damnning commentary (only to a point), but ultimately if we're all scientifically-minded then knowing that the internal targets were airbrushed for the public is a bit of a cerebral 'what?' I'd expect we're down with exploring on HN.
The first programming languages (static, duck typed, ...), database systems, web frameworks, anonymization frameworks, ... all had a lot of things that were either far from perfect or are now considered stupidity. But when nobody did what you did, when you are a pioneer everyone following would be a fool not to look at your work.
Also a nice example: Operating Systems. In the early days they were considered a waste of energy, time, resources. Why would you want to emulate computers on other computers (no, not visualization, but running multiple programs) or why would you use that valuable memory/storage space to have multiple programs on a machine at once? Those used to be actual questions. But that's a bit far fetched.
The project was/is a real pioneering project and I have lots of respect for people investing all their lives (more than two decades in this case!) so passionately into landing on a comet. Not too long ago that was science fiction.
The first message on the internet (arpanet) was meant to be "login", but it crashed after the o. I think those people got further, even though without doubt it didn't run as hoped for.
Well done, let's hope some interesting data was collected as a bonus.
Why didnt they just use nuclear energy?
